Improvement in exhausts for millstones



a. 1.. H. BEER NS. EXHAUST FOR MILLSTON'ES.

Patented Ocf..17,1876.

ILPEIE S, PHOTO LTHOGRAPHLI \vAsmNGToN 0 C GUSTAV L. H. BEE nus, or LuBEoK, GERMANY.

IMPROVEMENT IN EXHAUSTS FOR MILLSTONES.

Specification forming part of Letters Patent No. 183,248, dated October 17, 1376; application filed I I January l5, 1876. I

To all whom it may concern:

Be it known that I, GUSTAV L. H. BEHRNS, of Liibeck, Germany, have invented a new and useful Improvement in the Exhaust of Stones of Flour-Mills; and I do hereby declare the following to be a clear and exact description of the nature thereof, sufficient to enable others skilled in the art to which my invention appertains to fully understand, make, and use the same, reference being had to the accompanying drawings, making part of this specification, in which- Figure l is a sectional elevation, and Fig. 2'is a plan, partly sectional,-of amill em bodying my invention.

Similar letters of reference indicate corresponding parts in' the two figures.

My invention relates to improvements in the exhaust of millstones of flour-mills, whereby a more powerful exhaust may be employed than heretofore, resulting in a greatly increased yield from the millstones, while at the same time the presence of stive in the mill is avoided, moisture is effectually removed, and the stones are kept perfectly cool while grind 111g.

The invention consists of an air-tight casing, and an inner lining of sheet metal, and fabric for protecting the interior of the casing from the lower temperature of-the'surroundingair, and thus preventinganycondensation ofmoistme within the casing, so that all moist vapor resulting from the grinding shall pass off with the exhausted air.

It also consists in preventing the spout or funnel that conducts the grain and air into the eye, and the eye itself, from communicating with the interior of the casing.

11; further consists of meansfor forcing down the meal in the discharge-spout, and closing the same against the entrance of air.

It also consists of a screen, through which the whole of the air and moist vapor exhausted from the casing has to pass before escaping through the exhaust-aperture, the screen intercepting all particles of flour that the air would otherwise carry away withit, and so constructed as to present a large surface.

, It further consists of the exhaust-pipe protected from the cooling influence of the external air at the part nearest the millstone' casing, in order to prevent the moist vapor that passes away With the air from condensing in that part of the pipe until it has passed the bend of the pipe. After passing this bend the moisture is allowed to condense and flow in the pipe.

Referringto the drawings, Aand B represent the lower and upper millstones, respectively. .0 represents the casing, which islined with felt or other suitable non conducting material, D, and metal plating'E, so as to be air-tight, and protect the interior of the casing from the influence of the external atmosphere. F represents an air-tube concentrically surrounding the eye tube, by'which the grain is supplied to be ground. On the upper stone B there is a metal ring,,E[, which is let into and fixed in said stones, and has a V-shaped groove on its upper face, into which groove is fitted another ring, J, whose lower face corresponds to that of the groove of the'ring H, said ring J being prevented'from revolving in any suitable manner.

The ring is also connected to a flexible inclosing-band, L, suspended from the top of the casing, so that while the upper stone B and ring H revolve, the ring J, with the inclosure L, forms an air-tight separationbetwcen the eye of the stone and the interior of the easing, the ring J being allowed to accommodate itself to any eccentricity in the movement of the stone B. G represents an air-tube, connecting the upper part of the casing G with a fan or other exhauster. The bend of the tube is lined, like the casing O, with felt and metal plating D E, to pre.vent condensation oimoisture within the tube until the air flowing through it shall have passed the bend, and in the tube is a valve, U, for regulating the draft of air through it. M is the outlet for the flour. It is made with a bend, M, above which is a screw, N, caused to revol've by a strap working a pulley on the screw-shaft by a pulley on the stone-spindle. The effect of the screw N is to compress the flour on the inclined part of the bend below it, and thus render it sufficiently compact to prevent ingress of air to the interior of. the casing through the flour-passage M. P represents a cylindrical grating suspended from the cover of the casing G, and Q represents a porous "wool or hair fabrieattached to the upper rim.

of the grating P, and arranged zigzagwise, so as to form a series of radiating ridges and furrows, exposing a large surface for the passage of air through it, the fabric being sufficiently porous for the passage of air, but not for the passage of bll8 fil16 or dust; flour.

An arm, 1%, is attached to the grating P, and projects through the casing (l, and it is caused to oscillate in thedirection of "its length by a cam, wiper, or other convenient means, so as' to give a jigging movement to the grating P and fabric Q, forthepurpose. of shaking the dust from the under surface of the fabric Q; or the arm B may forthis purpose simply be struck slightly from time to time with a hammer. S is a gage fixed on-the casing, and communicating with thelspace in the casing outside of the gratingP, and also with the space above the fabric Q,-.so that it indicates the pressure within the spaces, respectively. The arrows in Fig. 1 indicate the course of the air drawnby the. action of the exhauster down the tube F, between theiworking faces of the millstones, thencethrough the pores of the fabric Q, and by the pipe Gtothe exhauster.

By the above described :arrangements it will be seen that a powerful exhaust can be applied to the casing Gthrough the tubeG, whereby a strong current of air willienter be: tween the lllillStOlleS:fI'Oll1 the air=tu be F,.resulting in a greatly-increased yield OflflOlll for a given motive power, any entrance of air into the casing except through the. eye of ;the millstone being prevented by the .inclosure L, and by the combined action of :the bend M and screw-blade N in the. meal spout. The air, on issuing from the circumference of the stones, has first to pass through the screening-surface Q 1 before it. can enter .the tube G, whereby all particles of 1 flour carried with it will be retained in thecasing, thus preventing any loss through theformation of stive, and dispensingwith the use of the usual stive-room. At the same .time anycondensation of moisture either between the mill: stones or; in *thccasing and in the bend of the tube =G, is prevented by the before-described non-conducting lining to the casing and bend of the-tube, whereby the formation of paste between the millstones and the consequent clogging of. the. griiiding surl'aces, is obviated. After passing the bend of allowed-to condense on the surfaces of the portion G, and to flow along the same, in order eventually to be discharged at the outside of themill.

.Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-- 1. The improvement in the constructionof millstonercasings, the same consisting of the exterior casing-O, the interiorwmetal plating D,,and tbeintermediate non-conducting materialE, substantiallyas and for the. purpose set; forth.

;2.u'l?he inclosing-bandflL, in-combination .withthe ring H, fixed to the upper stone, and

the-ring J, suspended from saidband L, the

two-rings having .a tongue and. groove, respectively, on adjacent faces, substantially as. and for the purpose set. forth.

The discharge-spout with the bend M and-thescrewN, for preventing ingress of air to the casing by the flour-spout,substantially asvherein. described.

4. The grating andscreen P and Q, for sift ingwthe air on its way to. the exhaust-pipe, substantiallyas herein described.

5. The combination, withthe millstone-casing, ofthei-exhaust-pipe G, having itsbend internallylined with non-conductin g material E and metal plating D,.and the portion G below; the bend unlined, substantiallyas and for; the; purposetset. forth.

G. L. H. BEHRNS.

Witnesses:

HEIN. -KASGH, DR. H.G6R:rz.

the tube G, the moisture contained in the exhausted air is 

